Almost every tennis player has at one time or another faced the tedious and time-consuming task of retrieving large numbers of tennis balls lying about the court, for example, after a session of practicing serves or other strokes. There are accordingly several devices now available to relieve the player of the tiring necessity of bending over and picking up the balls by hand, one by one.
One common ball retriever is a basket with bottom openings slightly smaller than the diameter of a tennis ball, and with a long handle. To pick up a ball from the court, the player, while standing upright and holding the long handle, pushes the basket down over the ball, which then passes through one of the bottom openings and is trapped in the basket. The main problem with using these baskets is that they usually allow the player to pick up no more than one or two balls at a time.
Much more efficient and less tiresome devices to retrieve balls from a court or other surface resemble shopping carts or "mowers." The user walks normally, pushing the cart before him, and arms that are mainly parallel to the surface of the court and that angle out from the cart try to funnel the balls to a central, revolving drum, belt, or scooper that lifts the balls up from the ground and deposits them into a basket. The tips of the arms are often curved relative to the arms themselves, or are provided with rollers or other devices, in order to support the ends of the arms on the court, or to reduce the tendency of the arms to snag on the net or damage walls.
Crown Manufacturing Company at present manufactures a cart of this type under the name "Ball Mower." In addition, the following patents disclose such carts:
U.S. Pat. No. 3,485,398 (Offner, Dec. 23, 1969); PA1 U.S. Pat. No. 3,593,868 (Folz, Jul. 20, 1971); PA1 U.S. Pat. No. 4,077,533 (Meyer, Mar. 7, 1978); PA1 U.S. Pat. No. 4,221,524 (Morris, Sep. 9, 1980); PA1 U.S. Pat. No. 4,252,490 (Keller, Feb. 24, 1981); PA1 U.S. Pat. No. 4,721,428 (Rohrer et al., Jan. 26, 1988); and U.S. Pat. No. 4,844,527 (Ray, Jul. 4, 1989).
These and other similar devices for retrieving balls have at least two disadvantages that are as common as they are irritating. First, while the user pushes the cart around the court, many balls often bounce away from the arms, particularly out from the curved ends. Also, when the cart changes directions, balls escape from the arms and bounce away, even when the cart is moving slowly.
Second, the collection baskets in these known devices typically do not hold balls securely until they can be reused or transferred to another device such as an automatic "serve cannon." In most known ball retrievers, such as those described in the patents referred to above, the balls that are lifted by the rotating drum, shaft, etc., are dropped either over an edge or through an opening in the collection basket. In many ball retrievers, the basket is open above, and some retrievers require a lid; in others, there is a second opening in the basket. In both cases, in order to remove the retrieved balls from the device, one must pour the balls either through the second opening or directly from the open basket. In both cases, either the balls must be poured slowly, with great care, and with frequent and cumbersome need to move the balls along by hand, or the balls tend to bounce out of the basket back onto the ground.
In the "Ball Mower," for example, the side walls of the ball collection basket are only about five inches high, in part to allow it to be mounted and removed from the main frame of the device. As balls are lifted from the tennis court and are deposited into the basket, balls tend to bounce over one another and many roll over the rim of the basket and out onto the court again. Later, when one wishes to remove the basket and dump the collected balls, for example, into a serve machine, one must tilt the basket, one rim of which is held behind a down-turned metal lip on the main frame of the device, and then pull the basket, still tilted, away from the main frame; balls then tend to fall out of the basket over the basket rim.
The object of this invention is to provide a ball retrieval device that collects and retains balls more efficiently than is now possible using existing devices. In particular, the invention has as its object to prevent balls from "escaping," both when they are being collected from an underlying surface such as a tennis court, and also when they are transferred to another device such as a ball-throwing machine in an easily attached and removed collection basket.